Process and apparatus for flash drying fluffed cellulose pulp
OwnerBengt Olof-Arvid Hedstrominventor
Life of this patent
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Abstract
Process and apparatus are provided for flash-drying cellulose pulp in a particulate form to be entrained in steam at an elevated pressure, employing steam both to heat the steam-entrained cellulose pulp via a heat-transfer surface, and to serve as carrier gas for the cellulose pulp that is being flash-dried.
Claims15
In the process for the flash drying of particulate cellulose pulp, comprising the steps (1) entraining the pulp particles in a gas, (2) establishing and maintaining a flow of the gas-particulate cellulose pulp mixture along a confined path, (3) transferring heat into the gas-particulate cellulose pulp mixture in a heat-transfer zone along the path, and (4) repeating step (3) in a successive series of heat-transfer zones, the improvement which comprises employing as the carrier gas steam under a pressure of at least 0.12 to 0.15 MPa;
- supplying heat to the heat-transfer zone as heating steam whose saturation pressure exceeds the pressure of the carrier steam;
- and then separating the fluffed cellulose pulp and carrier steam.
Apparatus for drying particulate cellulose pulp comprising a pressure conduit system defining a confined path for a flow of particulate cellulose pulp entrained in steam;
- means for establishing a flow of particulate cellulose pulp entrained in steam through the conduit system;
- a multiplicity of heat exchangers in the conduit system for transferring heat into the steam-particulate cellulose pulp mixture in heat exchanger zones;
- and at least one blower in the conduit system for imparting kinetic energy to the steam-particulate cellulose pulp mixture, the conduit system including a plurality of laterally adjacent, generally parallel conduit sections comprising spaced-apart heat exchangers, heat exchanger including therewithin a plurality of generally parallel tubes carrying the steam-entrained particulate cellulose pulp and a chamber through which the tubes pass and through which heating steam can be conducted over the outsides of the tubes to heat the tubes.
Dependencies are inferred from the claim text.